The goal of this preliminary study is to examine the effect of forced-exercise on parkinsonian motor signs in patients with Parkinson's disease (PD). Current medical and surgical approaches are expensive and are associated with a variety of side effects that may compromise the patient's quality of life. The development of a non-drug, non- surgical therapeutic approach to improve motor function would provide an attractive adjunct to current PD treatment approaches. Animal studies have shown that forced- exercise improves motor function and has neuroprotective qualities. The promising results from animal studies have not been translated to patients with PD. Differences in exercise modality used in animal versus human studies, forced vs. voluntary respectively, may account for the lack of evidence supporting the use of exercise as an intervention for PD. Models of PD provide a theoretical framework and rationale for the use of a forced-exercise intervention for PD patients. Decreased motor activation may limit PD patients'ability to generate voluntary movements at rates necessary, based on animal studies, to improve global motor functioning. We developed a lower extremity forced-exercise paradigm to augment the voluntary movements of PD patients to assist them in safely achieving an exercise rate greater than their voluntary rate. Our Preliminary Data indicate that patients completing an 8-week forced-exercise intervention exhibit a 35 percent improvement in clinical motor rating scores whereas patients completing a voluntary exercise intervention, of similar aerobic intensity, exhibited no improvements in clinical ratings. The primary aim of this project is to assess and compare the effects of forced versus voluntary exercise on motor function in patients with PD. We propose to conduct a preliminary prospective, single-center, single-blind controlled study. This preliminary project will be the first to directly compare the effects of forced and voluntary exercise on motor function using clinical and objective biomechanical outcomes in human PD patients. A total of 60 (n=20 per group) mild to moderate idiopathic PD patients will be randomized to a voluntary, forced or no-exercise control group. Clinical and biomechanical assessments will be performed at five time points: Baseline, mid-treatment, end of treatment (EOT), EOT + 4 and EOT + 8 weeks. It is hypothesized that patients completing forced-exercise will exhibit a global improvement in motor function compared to the voluntary and no-exercise groups. If forced-exercise is shown effective, it could become a viable alternative or adjunct therapy to pharmacologic or surgical approaches. The proposed cycling intervention is simple, can be self-directed, is relatively inexpensive (~$2,500 for system) and could immediately be translated to a inpatient or outpatient clinical setting or a patient'home. PUBLIC HEALTH RELEVANCE: The clinical relevancy of this study is important as it addresses the effectiveness of a novel and innovative exercise intervention for the treatment of Parkinson's disease. Preliminary data will be gathered to assess the efficacy of using forced-exercise in the treatment of Parkinson's disease. The proposed forced-exercise intervention augments the voluntary movements of Parkinson's patients to assist them in achieving a greater rate of exercise. Animal studies suggest exercising at higher rates improves motor performance and has neuroprotective qualities. Comparisons in motor function will be made between patients completing eight weeks of forced, voluntary or no-exercise. It is predicted that forced-exercise will result in greater improvements in motor function than voluntary or no-exercise. The proposed force-exercise intervention is safe and inexpensive. With minimal space and costs the intervention could be replicated in large and small physical and occupational therapy clinics and in the home of the patient. This intervention will potentially lead to better treatment of Parkinson's disease and improve the quality of life of those suffering from Parkinson's. Society will benefit from this project as individuals suffering from other neurological disorders or stroke could also be positively impacted by these results.